The present invention relates to an improved structure of pump stock of air pump used in fish bowl.
Prior bolt-connected two-piece structured pump stock, such as that disclosed in Taiwan Patent No. 73489, usually has following defects:
(1) The upper part and the lower part are assembled by screwing bolts through threaded holes while a rubber plate is placed between the two parts. Since the lower part is made of plastic material, the strength of the threaded holes is inevitably limited by the nature of its material. The bolts are made of metal which will easily damage the threads on the bolts if the worker fails to screw them accurately and perpendicularly into the threaded holes, thereby requiring removal and retightening of the bolts. Frequently, a considerable gap will result between the thread of hole and the bolt. Since the bolts will eventually become more loosely attached to the threads of the holes, both the upper part and the lower part of the pump stock will, under the vibration caused by the induction of the electromagnet, gradually be unable to tightly attach themselves to the rubber plate. The leakage of air from the resulting gap between the elements will deteriorate the entire function of the air pump accordingly. PA0 (2) Besides, to assemble the upper and the lower parts and the rubber plate by screwing bolts through threaded holes will relatively increase the labour and cost in pump production and die-making process, thereby causing a negative influence on productivity and efficiency.
It is an object of the present invention to provide an improved pump stock structure for an air pump used in a fish bowl by forming the pump cell and the air chambers that constitute the two major parts of an air pump in an inseparable one-piece structure to completely eliminate the above mentioned defects which found in prior art air pumps.
Another object of the present invention is to provide a method of manufacturing an air pump that would save so much costs in die-making process, assembly labours and working time that the economic benefit of the air pump and the competitive ability of which after being commercialized all can be greatly increased.
Still another object of the present invention is to provide an air pump for fish bowl, the pump stock of which has a flange at the bottom and can be placed into a recess of the pump casing so that the pump stock will not detach from its original position after long term use under the vibration generated during its operation.
A further important object of the present invention is to provide a much simplified design in the partition of air circulating passage which will greatly improve the air circulation and discharge efficiency.